https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108733
Bug ID: 108733
Summary: -Wanalyzer-use-of-uninitialized-value false positives
seen with __attribute__((cleanup))
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Target Milestone: ---
Created attachment 54439
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54439&action=edit
Reproducer
Am seeing various false positives in qemu from
-Wanalyzer-use-of-uninitialized-value with __attribute__((cleanup))
Seems to happen at -O1 and above with the attached reproducer, with both trunk
and gcc 12.2:
Trunk: https://godbolt.org/z/GdrY49151
12.2: https://godbolt.org/z/rjzvjd3qG
In function 'g_autoptr_cleanup_generic_gfree',
inlined from 'spapr_cap_get_string' at <source>:60:67:
<source>:15:3: warning: use of uninitialized value '*(void **)&val' [CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
15 | g_free(*pp);
| ^~~~~~~~~~~
'spapr_cap_get_string': events 1-4
|
| 60 | __attribute__((cleanup(g_autoptr_cleanup_generic_gfree))) char*
val = NULL;
| |
^~~
| |
|
| |
(1) region created on stack here
| |
(4) inlined call to 'g_autoptr_cleanup_generic_gfree' from
'spapr_cap_get_string'
|......
| 63 | if (value >= cap->possible->num) {
| | ~
| | |
| | (2) following 'true' branch...
| 64 | error_setg_internal((errp),
| | ~~~~~~~~~~~~~~~~~~~
| | |
| | (3) ...to here
|
+--> 'g_autoptr_cleanup_generic_gfree': event 5
|
| 15 | g_free(*pp);
| | ^~~~~~~~~~~
| | |
| | (5) use of uninitialized value '*(void **)&val' here
|
Compiler returned: 0
